Circuit Breaker trips

When I turned off the mains to my 200 amp panel, I checked the connections that are at the breaker box and found 1.25 volts at the neutral bus bar to ground. Will this cause the breaker to trip when I connect and turn on a breaker for bathroom lights. this only happens on 1 breaker. I also see one outlet with 1.25 volts when the breaker is of for this line. Do I have a short, or is 1.25 volts enough to trip a breaker. Wally